Electrode support



July 5, 1932. K. H KINGDON ET AL ELECTRODE SUPPORT Filed Oct. 29, 1927 Inventors: Kenneth H. Kingdom,

Lewl Tonks,

Their Attorney.

wmmmll mw Patented July 5, 1932 UNITED KENNETH H. KINGDON, OF SCHENECTADY, AND LEWI TOiNKS, OF SCOTIA, NEW YORK,

ASSIGNORS T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRODE SUPPGRT Application filed October 29, 1927. Sierial Il'o. 229,728.

The present invention relates to electron discharge devices and more particularly to an arrangement for supporting a filamentary cathode in such a device.

In amplifying systems microphonic noises due to vibrations of the filamentary electrode often cause considerable inconvenience. Various schemes have been devised to overcome this difiiculty among which has 0 been the use of spring supports for the electrodes. While such supports substantially prevent filament vibration, it is not always practical ordesirable to employ a support of this type and this is particularly true when the electrode system is rather large, as in amplifiers employing caesiated cathodes.

It is one of the objects of the present invention to provide a support for a filamentary electrode, which support is so disposed with respect to the filament that microphonic noises caused by filament vibration may be substantially eliminated.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, will best be understood from reference to the following specification when considered in connection with the accompanying drawing in which Fig. 1 shows a view partly broken away of an electron discharge device embodying the features of the present invention; Fig. 2 is a view, on an enlarged scale, of the cathode and cathode supporting means; while Fig. 3 is a detail view of a modified form of the invention.

Referring to the drawing, we have illustrated in Fig. 1 an electron discharge device comprising an evacuated receptacle 1, containing the usual anode 2, grid or control electrode 3, and cathode or filamentary electrode 4. The grid element 3 is supported on a flat metal plate 5 which is spaced from the anode 2, as indicated at 6 and connected to wires 7 and 8, one of which serves as a leading-in wire to supply a potential to the grid.

The anode 2 is supported on wires 9 and 10, one of which serves as a leading-in wire. A metal plate 11 is secured to a wire 11 connected to the anode supporting wires and carries a pellet containing a caesium compound from which caesium may be liberated during the exhaust of the tube. The pellet is enclosed in a metal cap 12 which is secured to plate 11 by flanged portions 13 on the cap.

The-filamentary electrode 4 comprises a coiled wire supported at its lower and upper ends by nickel wires 14 and 18 respectively. W'ires 14 and 18 are relatively heavy as compared with the filament 4. Wire 14 is secured to a leading-in wire 15 while a second leadingin wire 16 extends upwardly on the outside of anode 2 and is provided at its upper end-with a right angled extension 17 to which wire 18 is secured.

The filament is formed by winding it on a 15 mil mandrel so that the opening, at least through the end portions of the filament, is approximately of that diameter. The filament, between the end portions thereof, may 7 be somewhat drawn out, as clearly indicated in Fig. 2.

The filamentary electrode loosely surrounds the end portions of wires 14 and 18. H These wires are about 10 mils in diameter and project an appreciable distance into each end of the coiled filament making a loose rubbing or frictional contact with the filament. The ends of the filament are spot welded to the wires 14 and 18 at points 19 and 20, respectively, so that a rubbing contact is provided between each support 12 and 13 and the filament at points intermediate the ends of the filament. The frictional effect near the ends of the filament rapidly clamps out filament vibration and substantially eliminates the microphonic noises due to such vibration.

If desired, we may surround each end portion of the filament 4 with a tubular meta-l member 21 (Fig. 3) which is reduced in diameterat one end and secured at that end to the filament supporting wire by any suitable means. In this modification the filament is 5 secured to the wire 18 at a point adjacent the end of'the wire. The tubular member 21 is slightly larger in diameter than the diameter of the end portion of the coiled filament so that the tubular member makes a rubbing or frictional contact with the end portion of the filament when the latter vibrates.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a coiled filamentary electrode and means for supporting the elec trode, said means comprising a wire extending loosely an appreciable distance into one end of the filament and secured to the filament at a point intermediate the ends of the wire and adapted to provide a frictional contact between the wire and filament.

2. An electric discharge device comprising an envelope containing a cathode, electrostatic control member and an anode, 'said cathode consisting of a coiled filament which is normally subject to vibration under operating condition whereby microphonic noises are set up in the device, and means for reducing said vibrations, said means comprising a rod rigidly mounted in the envelope and secured to one end of the filament, said rod extending loosely within the filament coils and arranged to provide a rubbing Contact therewith at points intermediate the ends of the filament.

In Witness whereof, we have hereunto set our hands this 28th day of October, 1927.

KENNETH H. KINGDON. LEWVI TONKS. 

